<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        /* html,body{
            width: 100%;
            height: 100%;
        }
        .root{
            width: 100%;
            height: 100%;
        }
        .left{
            width: 200px;
            height: 100%;
            float: left;
            background-color: blue;
        }
        .right{
            width: 200px;
            height: 100%;
            float: left;
            background-color: red;
        }
        .center{
            width: calc(100% - 400px);
            height: 100%;
            float: left;
            background-color: green;
        } */
        body{
            min-width: 550px;
        }
        #container{
            padding-left: 200px;
            padding-right: 150px;
        }
        #container .column{
            float: left;
        }
        #center{
            width: 100%;
            background-color: green;
        }
        #left{
            width: 200px;
            margin-left: -100%;
            position: relative;
            right: 200px;
            background-color: red;
        }
        #right{
            width: 150px;
            margin-right: -150px;
            background-color: blue;
        }
    
    </style>
</head>
<body>
    <div id="container">
        <div id="center" class="column">center</div>
        <div id="left" class="column">left</div>
        <div id="right" class="column">right</div>
        <p>你的的的的的</p>
        <div>大苏打飒飒的</div>
        <span></span>
        <header></header>
    </div>
    <script> 
       var a = 1;
       //aaa
       var div = document.querySelector('.left');
       div.style.width = "300px";
       div = null;
    
    </script>
</body>
</html>